1. Field of the Invention
This invention relates to devices and methods used for supporting a disposable paper coffee filter in an erect position within the funnel portion of an automatic drip style coffee machine during the brewing process.
2. Description of the Prior Art
Automatic drip type coffee makers have been in use for some time which use specialized open brewing chambers or funnels designed to slowly filter heated water through the coffee into a coffee pot. These funnels are removably affixed to a housing which contains a heating element which heats a pre-measured amount of water before it is passed through the coffee contained in the funnel. These funnels come in a variety of shapes and sizes, the majority being frusto-conical in shape, with a few being cylindrical or square. A majority of these coffee makers use a disposable paper filter inserted into the funnel to prevent the grounds from being passed into the coffee pot below. Most of these disposable filters are cylindrical in shape and have a flat horizontal bottom surface and outwardly expandable fluted sides which are designed to conform to any shape funnel. The filters are inserted into the interior of the funnel which will generally have a flat horizontal apertured bottom surface and either perpendicular or outwardly inclined sides. One major problem with the paper filters is their tendency to collapse and fold over the coffee as the paper absorbs water. This results in the water flowing over the collapsed side of the filter, taking some of the coffee grounds with it out into the coffee pot below. Several manufacturers of the coffee machines have attempted to correct this problem by providing clips on the top edges of the funnels, but this only serves to retain two sides of the filters, with the two remaining sides left unsupported.
Devices used to support disposable coffee filters which are pertinent to my invention are disclosed in the following U.S. Pat. No. 4,765,896 dated Aug., 23, 1988, issued to Hartley et al; U.S. Pat. No. 4,735,719 dated Apr. 5, 1988, granted to Benedict; U.S. Pat. No. 4,728,425, issued to Sandvig on Mar. 1, 1988; and U.S. Pat. No. 4,656,932, dated Apr. 14, 1987, granted to Kopp. The Hartley device shows a wire basket filter support which is designed to be positioned between the filter and the funnel and not to prevent the sides of the filter from collapsing. The prongs on the bottom surface make it impossible to be inserted into the interior of the disposable paper filter. The Benedict device teaches a circular frusto-conically shaped plastic filter support which is adaptable to only a few styles of cylindrical funnels. Keeping the filter from being pushed down into the funnel when inserting the Benedict device would appear to present a problem due to the outward extending top flange. It is not altogether certain that when the Benedict device is used with the smaller funnels that the over hanging top flange does not interfere with the insertion of the funnel into the housing. The Sandvig device shows a cylindrical frusto-conically shaped plastic filter support having partial openings in the walls for passage of the coffee grounds. The remaining sections of the wall would cause the ground coffee to collect against the interior, either requiring the user to shake and redistribute the grounds through the openings, or risk the result of the brewed coffee being stronger than desired. Coffee will be stronger if it is passed through a thicker layer of grounds than poured over a thin, more widely distributed layer due to the fact the water takes longer to pass through the thicker layer and has more time to absorb the flavor from the grounds. The Kopp invention illustrates an adjustable circular retention ring which is adaptable to circular and frusto-conically shaped funnels only.